A fluorescein-linked immunoabsorbant assay (FLISA) was developed to measure antibacterial antibodies in secretions and serum. Formalin killed bacteria were coated onto one side of a double sided cellulose acetate disc. The disc was placed into samples of serum and saliva diluted into PBS pH 8.0 containing 0.25% Tween 20 and incubated with shaking for 30 minutes. The cellulose acetate disc was then transferred to a wash solution for 10 minutes and then into diluted antiglobulin reagent labelled with fluorescein isothiocyanate. After 20 minutes incubation the disc was transferred to a 10 minutes final wash. The amount of fluorescence bound to the disc was proportional to the amount of serum or salivary antibody bound to the bacteria. The fluorescence was measured in a committed fluorimeter.